moonbit_arc_ref.c

struct arc {
  int32_t rc;
  uv_mutex_t mutex;
};

typedef void* moonbit_reference_t;

struct arc_ref {
  struct arc arc;
  moonbit_reference_t ref;
};

typedef arc_ref *moonbit_arc_ref_payload;

typedef moonbit_arc_ref_payload* moonbit_arc_ref_t;


void moonbit_uv_reference_finalize(void* object) {
  moonbit_arc_ref_t obj = (moonbit_arc_ref_t)(object);
  if (obj) {
    moonbit_arc_ref_payload arcref_payload = *obj;
    // Critical Section BEGIN
    uv_mutex_lock( &arcref_payload->arc.mutex);
    int32_t rc = arcref_payload->arc.rc;
    moonbit_uv_trace("mutex->block->arc = %d -> %d\n", rc, rc - 1);
    arcref_payload->arc.rc -= 1;
    uv_mutex_unlock( &arcref_payload->arc.mutex);
    // Critical Section END
    if (rc > 1) {
      return;
    }
    // now this callee is unique owner
    uv_mutex_destroy(&arcref_payload->arc.mutex);
    moonbit_decref(arcref_payload->ref);
    free(arcref_payload);
  }
}

void mooonbit_uv_reference_make(moonbit_reference_t* ref) {
  moonbit_arc_ref_t res = (moonbit_arc_ref_t)moonbit_make_external_object(
    moonbit_uv_reference_finalize,
    sizeof(moonbit_arc_ref_payload)
  );
  moonbit_arc_ref_payload arcref_payload = (moonbit_arc_ref_payload)malloc(sizeof(struct arc_ref));

  *res = arcref_payload;
  arcref_payload->ref = ref;
  arcref_payload->arc.rc = 1;
  uv_mutex_init(&arcref_payload->arc.mutex);
}

moonbit_arc_ref_t mooonbit_uv_reference_share_payload(moonbit_arc_ref_t self) {
  moonbit_arc_ref_t res = (moonbit_arc_ref_t)moonbit_make_external_object(
    moonbit_uv_reference_finalize,
    sizeof(moonbit_arc_ref_payload)
  );
  moonbit_arc_ref_payload arcref_payload = *self;
  // Critical Section BEGIN
  uv_mutex_lock(&arcref_payload->arc.mutex);
  arcref_payload->arc.rc += 1;
  uv_mutex_unlock(&arcref_payload->arc.mutex);
  // Critical Section END
  *res = arcref_payload;
  moonbit_decref(self);
}